Delta Flight 191 and United Flight 173 Crash Investigations

Introduction

Accident investigations vary considerably from one crash to another. This paper examines the investigations of two plane crashes: Delta Airlines Flight 191 and United Airlines Flight 173. The Dallas investigation benefited from good accessibility to the crash site, with multiple first-responding organizations from local municipalities, though it suffered from a slow initial reaction time. United Airlines Flight 173, by contrast, was clearly caused by pilot error, as the plane ran out of fuel while the captain was distracted by landing gear issues.

Delta Airlines Flight 191 was a great tragedy involving many deaths. According to the research, "Delta Airlines Flight 191 was a regularly scheduled passenger flight between Fort Lauderdale, Florida and Los Angeles, California, with an en route stop at the Dallas/Fort Worth International Airport, Texas (DFW)" (Federal Aviation Administration, 2013). The entire flight proceeded smoothly until the plane began its approach for the stopover in Dallas. The flight encountered a weather cell, which redirected it through the Blue Ridge area and put the aircraft in a rainstorm as it waited to land. Two planes prior to Flight 191 had passed through the same weather with little incident. Yet when Delta Flight 191 attempted to land, "the decreasing trend of the headwind reversed itself, and along with the high thrust condition, resulted in a rapid increase in airspeed from 129 to 147 knots" (Federal Aviation Administration, 2013). The pilots initially decided to land, believing the weather cell was not as extreme as it ultimately proved to be. "Delta Air Lines Flight 191 went down in prime time. At 6:05 p.m. Aug. 2, 1985, a Friday afternoon, television stations were in the midst of their newscasts when the flight from Fort Lauderdale, Fla., flew into a storm" (Dickson, 2010). Winds exceeding 80 miles per hour forced the plane to the ground. Before final impact, the aircraft struck a vehicle on one of Texas's major highways, killing a motorist. In total, 136 people died.

United Airlines Flight 173 presented a very different scenario. The research states that "on December 28, 1978, United Airlines, Inc., Flight 173, a McDonnell-Douglas DC-8-61 (N8082U), was a scheduled flight from John F. Kennedy International Airport, New York, to Portland International Airport, Portland, Oregon, with an en route stop at Denver, Colorado" (Air Disasters, 2013). The nature of this crash differed markedly from the Dallas incident. Records show that "about 1815 Pacific standard time on December 28, 1978, United Airlines, Inc., Flight 173 crashed into a wooded, populated area of suburban Portland, Oregon, during an approach to the Portland International Airport" (Air Disasters, 2013). Fortunately, only 10 people were killed in this crash, compared to the far higher death toll in Dallas.

Crash Dynamics and Causes

The Dallas crash was driven entirely by a meteorological phenomenon. According to the research, "within one second, large variation in wind components along all three axes of the aircraft were noted. Indicated airspeed decreased from 140 to 120 knots, the vertical wind reversed from a 40 feet per second downdraft to a 20 feet per second updraft, and a severe lateral gust struck the airplane. This gust resulted in a very rapid roll by the airplane to the right, requiring almost full lateral flight control authority to level the wings" (Federal Aviation Administration, 2013). Ultimately, the plane crashed because it entered a volatile weather cell. A wind shear threw the aircraft off balance, causing it to strike "the ground in a left-wing-low attitude, careening toward and striking two water towers on the airport property. The fuselage rotated counter-clockwise after the left wing and cockpit area struck the water tanks. A large explosion obscured the witnesses' view momentarily, and then the tail section emerged from the fireball skidding backwards" (Federal Aviation Administration, 2013). Upon impact, the plane was torn apart. The fuselage separated from the tail, and a massive fire erupted. "In the final impact, the left wing struck the ground, then the wing and cockpit hit water tanks on airport property, spinning the fuselage counterclockwise" (Dickson, 2010). The pilot had applied full thrust in an attempt to escape the weather, but this decision backfired and increased the severity of the crash. "Most of the plane disintegrated, although the charred tail was preserved. In photos, the tail section became a widely recognized symbol of the crash" (Dickson, 2010). Further investigation confirmed that weather was the primary factor in bringing the plane down.

For United Flight 173, the crash dynamics were entirely different. Initially, "United Flight 173, a DC-8 approaching Portland, Ore., with 181 passengers, circled near the airport for an hour as the crew tried in vain to sort out a landing gear problem" (Noland, 2012). Preoccupied with the landing gear issue, the crew failed to adequately monitor the impact the delay was having on the fuel supply, which diminished rapidly. Although "gently warned of the rapidly diminishing fuel supply by the flight engineer on board, the captain — later described by one investigator as 'an arrogant S.O.B.' — waited too long to begin his final approach. The DC-8 ran out of fuel and crashed in a suburb, killing 10" (Noland, 2012). Despite multiple communications between the captain, crew, and ground personnel, the pilot made the ill-fated decision to continue circling in order to resolve the landing gear problem. "Contributing to the accident was the failure of the other two flight crewmembers either to fully comprehend the criticality of the fuel state or to successfully communicate their concern to the captain" (Air Disasters, 2013). This critical error produced serious consequences. The research shows that "the plane crashed about 6 miles southeast of the airport. The aircraft was destroyed; there was no fire. Of the 181 passengers and 8 crewmembers aboard, 8 passengers, the flight engineer, and a flight attendant were killed, and 21 passengers and 2 crewmembers were injured seriously" (Air Disasters, 2013).

There were also notable differences in where each crash occurred. United Flight 173 went down in a wooded residential area rather than near an airport runway, creating the potential for additional ground casualties — though fortunately none occurred. "There were many occupied houses and apartment complexes in the immediate vicinity of the accident, there were no ground casualties and no post-crash fire" (Air Disasters, 2013). The consequences of this flight were therefore far less severe than those seen in Dallas.

The human impact of the Dallas crash was enormous. The aftermath of the investigation deeply affected first responders and investigators alike. "After Flight 191 went down, firefighters, police and many other officials with the airport's in-house public safety department as well as neighboring cities such as Grapevine and Irving spent days recovering bodies and preserving evidence, and then dealing with the psychological effects of what they had seen" (Dickson, 2010). Many first responders were unprepared for the carnage they encountered. Some were injured on the scene, while others were profoundly affected by the visual images of the crash and its many victims. Years later, "several first-responders and family members of victims attended the memorial ceremony" at the 25th anniversary in 2010, "where a three-foot granite monument was dedicated" (Dickson, 2010). It was an investigation that left a lasting mark on everyone involved.

In Oregon, the human impact was far less severe. Fewer passengers died, and the crash site was more contained. "The 10 occupants killed in the crash were located between the flight engineer's station in the cockpit and row 5 in the passenger cabin. All of the passengers who were killed had been located on the right side of the cabin" (Air Disasters, 2013) — the section of the aircraft that sustained the most catastrophic damage. There was no post-crash fire, which reduced overall destruction and allowed first responders to work more effectively. Survivors were far more easily extracted from the wreckage, enabling rescue personnel to save more lives.

First Responder Accessibility and Response

Because of the Dallas crash site's close proximity to Dallas/Fort Worth International Airport, accessibility for first responders was relatively straightforward. Responding organizations included the DFW Airport Department of Public Safety, the Texas Department of Public Safety, the Irving Fire Department, the Irving Police Department, and members of the Dallas Police Department. Safety organizations were notified immediately after the crash, with some units arriving within minutes. Approximately ten minutes after impact, the initial fire that had engulfed the cabin was sufficiently controlled to begin searching for survivors.

In Oregon, accessibility was more challenging. The plane had come down in a wooded residential area. Reports indicate that "the plane crashed in the jurisdiction of Multnomah County Rural Fire Protection District No. 10" (Air Disasters, 2013). The absence of a post-crash fire, however, made survivor recovery considerably easier. "Three fire departments sent personnel and equipment to the scene: The Port of Portland (Airport) Fire Department; Multnomah RFPD No. 10, and the City of Portland Fire Bureau. A total of 39 fire units and 108 on-duty fire personnel responded to the scene" (Air Disasters, 2013). There were no significant communication problems, as was also the case in the Dallas response. However, United Flight 173 did not experience the same notification delays seen in Dallas, despite the crash site being farther from the airport.

In the case of the Dallas flight, several aspects of the investigation's conclusions warrant scrutiny. At the time of the crash, the National Transportation Safety Board (NTSB) declared that the flight went down primarily because of pilot error, arguing that the crew should have avoided the weather cell and chosen to fly out of the thunderstorm rather than attempt a landing. However, despite "the lack of training cited by the NTSB, this crew really did a great job. There isn't much to wind shear escape other than applying max thrust and pitching for best climb" (Flannigan, 2010). In reality, it was the unusual weather and the microburst wind shear that brought the plane down, and the crew had done what they believed was best. "Crew members saw the storm while approaching D/FW but remained mostly unalarmed, according to transcripts of their on-board conversations recovered by flight recorders" (Dickson, 2010). The crew had very little time to react — only seconds to attempt to keep the aircraft airborne after encountering the microburst and wind shear.

Conclusion

Both crashes left lasting marks on the aviation industry. Delta Flight 191 transformed how pilots and aviation authorities approach wind shear and microburst phenomena, while United Flight 173 gave rise to Crew Resource Management as an industry standard. Together, these two accidents illustrate how different the causes, consequences, and investigative outcomes of plane crashes can be — and how much each tragedy contributed to making modern aviation safer.